Because this is a definition.
It isn't....
"Everything I think God means or attach to God or even statements about God are Truth"
I'm not talking about conceptions about The Truth, I am talking quite literally, not figuratively, not metaphorically, about The Truth.
The Truth is God.
To say, "God is an apple" is not the same thing as "God is The Truth".
What I am saying is only nonsensical to you because you haven't yet accepted what God is.
You have a particular idea in your head about what God is and what God means, but I am telling you that these preconceived ideas are going to get in the way.
So throwing aside religion, culture, traditions and the like for a moment... The one thing that must first be absolutely accepted as fact is that God literally is The Truth. That is God.
And there are many different religions who will say all sorts of things about The Truth, but The Truth is, and it is what it is.
Understanding that this is what God means, realize that the atheist is denying this True God alongside all of the other false gods. The only way to make atheism true in this case, is to make God into something other than what God is. All atheist arguments are contingent on ignoring the reality of this One God.
Believing God does not imply believing anything other than The Truth exists. So you may not identify as a Christian, a Muslim, a Sikh, a Hindu, etc. But you can still believe with a certainty that God exists. Supreme Being literally means that existence is a necessary quality of God because that is what the word being means.
So really, the only thing I am trying to tell you is that The Truth is God, and this is what educated people believe. Educated people are not masochistic enough to debate the existence of truth with people who say there is no truth. I am on a fools mission for loves sake. Otherwise, what is the point? I may have something to offer here, I have unique gifts. I pray my mission isn't in vain.
So it is absolutely necessary that it is understood that when I say "God", this means "The Ultimate Reality".
Otherwise, we aren't talking about the same thing. If you believe The Ultimate Reality exists, you already believe in God whether or not you know to call God by name.